Solid state electronic devices can be mounted on submounts that provide mechanical support, electrical connection, and thermal dissipation, as well as other functionality, for the electronic devices. For example, solid state light sources, such as semiconductor light emitting diodes, can be mounted on submounts as disclosed in U.S. Pre-grant Publication No. 2007/0253209 which is assigned to the assignee of the present invention and which is incorporated herein by reference as if fully set forth herein. The submounts may further be provided in packages that provide protection, color selection, focusing and the like for light emitted by the light emitting device. A solid state light emitting device may be, for example, an organic or inorganic light emitting diode (“LED”). Some packages for light emitting diodes are described in U.S. Pre-grant Publication Nos. 2004/0079957, 2004/0126913, and 2005/0269587 which are assigned to the assignee of the present invention, and which are incorporated herein by reference as if set forth fully herein.
Alumina-based submounts for electronic devices can be formed using green state alumina sheets. Green state alumina tape, which is malleable, can be press-molded into various shapes and can be punched, cut or drilled to form vias or other features therein. For example, referring to FIG. 1, a submount 5 for mounting an electronic device can be formed by punching or drilling via holes 12 in a substrate of green state alumina 10. As used herein, “substrate” refers to a layer of material that provides mechanical support for an object, such as an electronic device. A submount includes a substrate and therefore provides mechanical support for an electronic device as well, but a submount may also include features that provide electrical connections such as die attach pads, electrical traces, etc., features that dissipate thermal energy, features that provide optical functionality, such as reflectors and/or lenses, and/or other functionality. The via holes 12 can be plated and/or filled with conductive material 14, such as copper or aluminum, and the green state alumina tape 10 and the vias 12, 14 can be co-fired to transform the green state alumina tape 10 into an alumina substrate 10. Contact pads 16, 18, that electrically connect to the vias 12, 14, can be formed on opposite sides of the alumina substrate 10, for example by plating and patterning metal traces. In this manner, electrically and thermally conductive paths can be formed from one side of the substrate to the other.